Pinless power coupling

ABSTRACT

A pinless power coupling arrangement comprises at least one pin-less power jack, the power jack comprising a primary coil shielded behind an insulating layer for inductive coupling to a pin-less power plug. The power plug comprises a secondary coil wherein said insulating layer is substantially flat and the power plug and the power jack may be aligned by an alignment means. Various such alignment means are discussed as are enabled surfaces for supporting inductive power jacks and inductive plugs coupled to various appliances.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/499,335, filed Apr. 27, 2017, which in turn is acontinuation of U.S. patent application Ser. No. 14/024,051, filed Sep.11, 2013, now U.S. Pat. No. 9,666,360, which in turn is a continuationof U.S. patent application Ser. No. 12/524,987, filed Mar. 10, 2010, nowU.S. Pat. No. 8,629,577, which in turn is a U.S. National Phase filingunder 35 U.S.C. § 371 of PCT Patent Application No. PCT/IL2008/000124,filed Jan. 28, 2008, which is based upon and claims the benefit of U.S.Provisional Patent Application Ser. No. 60/897,868, filed Jan. 29, 2007,U.S. Provisional Patent Application Ser. No. 60/935,694, filed Aug. 27,2007, and U.S. Provisional Patent Application Ser. No. 61/006,488, filedJan. 16, 2008, each of which is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention is directed to providing a pinless power couplingsystem. More particularly the invention is related to efficientinductive power transmission across substantially flat surfaces.

BACKGROUND

Electrical connections are commonly facilitated by the use of plugs andjacks. Power jacks are fixed connectors which are stationary relative tothe surface into which they are embedded. Power plugs are movableconnectors which are adapted to electrically couple with power jacks.The plug-jack coupling allows a movable device hardwired to the plug tobe selectively connected to a power jack and disconnected and removedwhen required. In such electrical couplings it is common for the plugand jack to be mechanically coupled together and conductively connectedusing a pin and socket combination. The pin and socket coupling providesa way to align the plug to the jack efficiently and to prevent the twofrom becoming disconnected while in use and the pin, typically copper orbrass, forms a conducting contact with a conductive element lining thesocket. Where power is being transmitted, such as in a mains powerpoint, where there is a danger of injury from electrocution, it iscommon that the pin is provided on the plug so that the live power linesmay be safely shielded within the sockets of the power jack.Nevertheless, since the live power lines are not fully insulated thereis a risk of injury associated with mains sockets, particularly tochildren who may be tempted to push small fingers or other objects intoa live socket. It is therefore common to provide additional protectionsuch as through the use of socket guards and the like.

Moreover, a socket if not maintained, collects dust which may impedeelectrical connection or even clog the socket, making insertion of thepin difficult. For this reason, power sockets are typically mounted uponwalls and are not angled upwards. This configuration also reduces therisk of shorting or electrocution as a result of liquid spillages.

Inductive power connectors for providing insulated electrical connectionare known. For example U.S. Pat. No. 7,210,940 to Baily et al. describesan inductive coupling for transferring electrical energy to or from atransducer and measuring circuit. Baily's system consists of a maleconnector having a single layer solenoid wound on a ferromagnetic rodand a female connector having a second single layer solenoid. Byinserting the male connector into the female connector, the twosolenoids are brought into alignment, enabling inductive energy transfertherebetween. This coupling provides a sealed signal connection withoutthe disadvantages of having exposed contact surfaces.

In Baily's system the female connector still represents a socket and themale connector a pin. Although there are no exposed contact surfaces,such electrical power jacks cannot be located upon surfaces which needto be flat such as table tops, counters and the like. Because suchsurfaces are often precisely where electrical connection would be mostconvenient, this results in unsightly and inconvenient, extensive powerconnecting cables.

Other electrical power transmission systems allowing a power receivingelectrical device to be placed anywhere upon an extended base unitcovering a larger area have been proposed. These provide freedom ofmovement without requiring the trailing wires inherent in Baily. Onesuch example is described in U.S. Pat. No. 7,164,255 to Hui. In Hui'ssystem a planar inductive battery charging system is designed to enableelectronic devices to be recharged. The system includes a planarcharging module having a charging surface on which a device to berecharged is placed. Within the charging module, and parallel to thecharging surface, is at least one, and preferably an array of primarywindings that couple energy inductively to a secondary winding formed inthe device to be recharged. Hui's system also provides secondary modulesthat allow the system to be used with conventional electronic devicesnot supplied with secondary windings.

Such systems are adequate for charging batteries, in that they typicallyprovide a relatively low power inductive coupling. It will beappreciated however, that extended base units such as Hui's chargingsurface which allows energy transfer approximately uniformly over thewhole area of the unit, are not generally suitable for providing thehigh energy requirements of many electric devices.

U.S. Pat. No. 6,803,744, to Sabo, titled “Alignment independent and selfaligning inductive power transfer system” describes an inductive powertransfer device for recharging cordless appliances. It also addressesthe problem of pinlessly aligning a secondary inductive coil to aprimary inductive coil. Sabo's device includes a plurality of inductorsarranged in an array and connected to a power supply via switches whichare selectively operable to activate the respective inductors. Theinductors serve as the primary coil of a transformer. The secondary coilof the transformer is arranged within the appliance. When the applianceis positioned proximate to the power transfer device with the respectivecoils in alignment, power is inductively transferred from the device tothe appliance via the transformer.

Nevertheless the need remains for a cost effective and efficient pinlesspower coupling mechanism and the present invention addresses this need.

SUMMARY OF THE INVENTION

It is an aim of the invention to provide a pinless power couplingarrangement comprising at least one pinless power jack comprising aprimary coil shielded behind an insulating layer for inductive couplingto a pinless power plug comprising a secondary coil wherein theinsulating layer is substantially flat and the pinless power plug andthe power jack are alignable by an alignment means.

Typically the alignment between said power plug and said power jack ismaintained whilst said power plug is rotated through 360 degrees about acentral axis.

Optionally the alignment is being selected from visual, audible andtactile means.

Optionally the insulating layer is translucent allowing direct visualalignment.

Alternatively insulating layer is visually marked to indicate thelocation of the power jack allowing direct visual alignment.

Optionally the alignment means comprises an illuminated indicatorconfigured to indicate when a plug is aligned to the power jack.

Typically the illuminated indicator is selected from the groupcomprising LEDs, an LED scale, and LCD screens.

Preferably the visual indicator is configured to provide a graduatedindication of proximity to full alignment.

Optionally, the alignment means comprises an audible indicatorconfigured to indicate when a plug is aligned to the power jack.

Typically the audible indicator is selected from the group comprising atleast one buzzer, at least one bell, at least one speaker, at least oneclapper and any combination thereof.

Optionally, the audible indicator is configured to provide graduatedindication of proximity to alignment.

Preferably the alignment means is a tactile indicator comprising atleast one magnetic snag configured to couple with at least one magneticanchor carried by the pinless power plug.

In preferred embodiments the magnetic snag has an annular configurationsuch that an annular magnetic anchor engages said magnetic snag at anyangle.

Typically the magnetic snag is selected from the group comprising atleast one permanent magnet, at least one electromagnet and at least oneferromagnetic element. Optionally the magnetic anchor is selected fromthe group comprising at least one permanent magnet, at least oneelectromagnet and at least one ferromagnetic element. Preferably thepolarities of the magnetic snag and magnetic anchor are selected suchthat the power plugs will only align with compatible power jacks.

Alternatively the alignment means is a tactile indicator selected fromthe group comprising at least one sucker, at least one hook-and-looparrangement, at least one ridge-and-groove arrangement and combinationsthereof.

It is a further aim of the invention to provide a power surfacecomprising an array of pinless power jacks.

Typically the power surface is a horizontal work surface. Alternatively,the power surface is a vertical wall. Alternatively again, the powersurface is a ceiling.

Still another aim of the invention is to provide a pinless power plugcomprising at least one secondary coil for inductive coupling to apinless power jack shielded behind an insulating layer wherein theinsulating layer is substantially flat and the power plug and the powerjack are alignable by an alignment means.

Optionally, the pinless power plug comprises at least two secondarycoils. Preferably the pinless power plug is adapted for coupling with anarray of said primary coils wherein said at least two secondary coilsare offset by a distance which is different to the intercoil spacing ofsaid array of said primary coils.

Optionally the alignment means comprises a visual indicator configuredto indicate when the plug is aligned to a power jack.

Typically the visual indicator is selected from the group comprisingLight Emitting Diodes (LEDs), LED scales and LCD screens.

Preferably the visual indicator is configured to provide a graduatedindication of proximity to full alignment.

Optionally the alignment means comprises an audible indicator configuredto indicate when the plug is aligned to a power jack.

Typically this audible indicator is selected from the group comprisingbuzzers, bells, speakers, clappers and combination thereof.

Optionally the audible indicator is configured to provide a graduatedindication of proximity to full alignment.

Preferably the alignment means is a tactile indicator comprising atleast one magnetic anchor configured to couple with at least onemagnetic snag of at least one pinless power jack.

Typically magnetic anchor is selected from the group comprises elementsselected from the list of permanent magnets, electromagnets andferromagnetic elements.

Alternatively the alignment means is a tactile indicator.

Alternatively the alignment means is selected from the group comprisingsuckers, hook-and-loop arrangements, corresponding ridge-and-groovearrangements and combinations thereof.

Optionally the pinless power plug is connectable to at least oneelectric load by a power cord.

Alternatively the pinless power plug is hardwired to at least oneelectric load.

In another aspect, the present invention is directed to providing apinless power plug and an electric device permanently coupled togetherin a unitary device.

One embodiment of the invention is directed to a light fittingcomprising a pinless power plug coupled to a light source.

In another embodiment, the pinless power plug is coupled to a atraveling power socket having at least one socket for pinned plugs andserves as an adaptor for retrofitting power devices of the prior art topower jacks of the invention.

Preferably the pinless power jack provides power in the range of between1 watt and 200 watts. Typically the pinless power jack provides power inthe range of between 5 watts to 110 watts.

In preferred embodiments of the invention, the power couplingadditionally comprises a regulator. Optionally the regulator is a signaltransfer system.

It is therefore another aim of the present invention to provide a signaltransfer system for regulating power transfer between a primary coilbehind a surface layer and a secondary coil brought into alignment withthe primary coil; the signal transfer system comprising at least oneoptical transmitter in front of a surface layer for transmittingelectromagnetic radiation of a type and intensity capable of penetratingthe surface layer and being received by at least one optical receiverbehind the surface layer.

Preferably the optical transmitter comprises a light emitting diode.Optionally the optical transmitter transmits an infra red signal.Typically, the optical receiver is selected from the group comprising:phototransistors, photodiodes and light dependent resistors.

In preferred embodiments the surface layer is constructed from amaterial selected from the group comprising glass, plastic, mica,formica, wood, wood veneer, canvas, cardboard, stone, linoleum andpaper. Optionally, the surface layer comprises a generally opaque panelpunctuated by at least one optical path for guiding the optical signalto the optical receiver. Typically, the optical path is selected fromthe group comprising: waveguides, optical fibers and windows.

The optical signal may carry encoded data pertaining to at least one ofthe group comprising:

presence of an electric load;

required operating voltage for the electric load

required operating current for the electric load;

required operating temperature for the electric load;

measured operating voltage for the electric load;

measured operating current for the electric load;

measured operating temperature for the electric load, and

a user identification code.

Optionally, the inductive energy couple is a device selected from thegroup comprising: a transformer, a DC-to-DC converter, an AC-to-DCconverter, an AC-to-AC converter, a flyback transformer, a flybackconverter, a full-bridge converter, a half-bridge converter and aforward converter. Typically, the primary coil is galvanically isolatedfrom the secondary coil.

In preferred embodiments the optical receiver is coaxial with saidprimary coil and said optical receiver is coaxial with said secondarycoil such that when said primary coil is aligned to said secondary coil,and said optical receiver is aligned to said optical transmitter.

A further aspect of the invention is directed to provide a method forregulating power transfer across an inductive coupling comprising aprimary coil behind a surface layer and a secondary coil in front of thesurface layer, the method comprising the following steps:

-   -   a. providing at least one optical transmitter in front of the        surface layer;    -   b. providing at least one optical receiver behind the surface        layer;    -   c. communicating a regulating signal to the optical transmitter;    -   d. the optical transmitter transmitting the regulating signal as        electromagnetic radiation of a type and intensity capable of        penetrating the surface layer;    -   e. receiving the electromagnetic radiation by the optical        receiver; and    -   f. adjusting the power transfer according to the regulation        signal.

Optionally, the regulation signal carries details of power requirementsof the load. Typically, the method regulates power transfer across aninductive coupling wherein the optical signal is provided by monitoringat least one operating parameter of the electric load and encoding themonitored parameter data into the optical signal. Alternatively oradditionally, the method regulates power transfer across an inductivecoupling wherein the optical signal carries data pertaining to at leastone parameter selected from the group comprising operating voltage,operating current and operating temperature. Preferably, the methodcomprises the preliminary step of detecting the presence of an electricload.

The term “jack” as used herein refers to any fixed connector forreceiving and for providing power to an electrical plug. The term “jack”is not defined by the gender of the connector and does not indicatehaving sockets for receiving protruding pins of a plug.

The term “plug” as used herein refers to any moveable connector forelectrically connecting to a jack as above. The term “plug” is notdefined by the gender of the connector and does not imply havingprotrusions for fitting into a socket.

It will be noted that although gender based definitions are sometimesused for the terms jacks and plugs, the above definitions are in keepingwith IEEE STD 100 and ANSI Y32.16 standards.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the invention and to show how it may becarried into effect, reference will now be made, purely by way ofexample, to the accompanying drawings.

With specific reference now to the drawings in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presentinvention only, and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention. In this regard, noattempt is made to show structural details of the invention in moredetail than is necessary for a fundamental understanding of theinvention; the description taken with the drawings making apparent tothose skilled in the art how the several forms of the invention may beembodied in practice. In the accompanying drawings:

FIG. 1 is a block diagram schematically representing the main featuresof an inductive power transfer system according to one embodiment of thepresent invention;

FIG. 2a is a schematic representation of a pinless power couplingconsisting of a pinless power jack and a pinless power plug according toanother embodiment of the present invention;

FIG. 2b-d show three exemplary applications of the power coupling ofFIG. 2a providing power to a computer, light bulb and pinless poweradaptor;

FIGS. 3a and 3b show an exemplary configuration for an induction coil inschematic and exploded representation respectively;

FIGS. 4a-c show three exemplary tactile alignment mechanisms foraligning a pinless power plug to a pinless power jack according tofurther embodiments of the invention;

FIGS. 5a-h show eight magnetic configurations for use in a tactilealignment mechanism for a pinless power coupling;

FIGS. 6a-e show three exemplary plug-mounted visual alignment mechanismsfor a pinless power coupling;

FIGS. 7a-d show four exemplary surface-mounted visual alignmentmechanisms for a pinless power coupling;

FIGS. 8a and 8b show audible alignment means for use with the pinlesspower coupling according to still further embodiments of the invention;

FIG. 9 shows an exemplary optical transmitter for regulating powertransfer to a computer via a pinless power coupling;

FIG. 10 is a block diagram illustrating the main features of anexemplary signal transfer system for initiating and regulating inductivepower transfer from the pinless power plug;

FIG. 11a shows a power surface including an array of pinless power jacksin accordance with yet another embodiment of the invention;

FIG. 11b shows a power plug with secondary coils spaced apart, lyingover a power surface comprising overlapping primary coils arranged inlayers.

FIG. 11c shows two movable pinless power plugs lying upon the powersurface of FIG. 11 a;

FIG. 11d shows a power plug provided with two secondary coils forcoupling with primary coils of the power surface of FIG. 11 a;

FIGS. 12a-c show three exemplary applications of the power surface ofFIG. 11a providing power to a computer, light bulbs, and pinless poweradaptors, respectively; and

FIG. 13 is a flow diagram flowchart showing a method for transferring anoptical regulation signal between a primary unit and a secondary unitvia an intermediate layer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made to FIG. 1 which is a 1000 for pinlessly providingpower to an electric load 140, according to a first embodiment of theinvention. The power transfer system 1000 includes a pinless powercoupling 100, an alignment mechanism 200 and a power, regulator 300.

The pinless power coupling 100 comprises a pinless power jack 110 and apinless power plug 120. The pinless power jack 110 includes a primaryinductive coil 112 wired to a power supply 102 via a driving unit 104.The pinless power plug 120 includes a secondary inductive coil 122 whichis wired to the electric load 140. When the secondary coil 122 isbrought close to the primary coil 112 and a variable voltage is appliedto the primary coil 112 by the driving unit 104, power may betransferred between the coils by electromagnetic induction.

The alignment mechanism 200 is provided to facilitate aligning theprimary coil 112 with the secondary coil 122 which improves theefficiency of the inductive coupling. The regulator 300 provides acommunication channel between the pinless power plug 120 and the pinlesspower jack 110 which may be used to regulate the power transfer.

The various elements of the pinless power transfer system 1000 may varysignificantly between embodiments of the present invention. A selectionof exemplary embodiments are described herebelow. These are not to beunderstood as limiting the scope of the invention in any way.

Pinless Power Coupling

Reference is now made to FIG. 2a which shows a pinless power coupling100 according to a second embodiment of the invention. A pinless powerjack 110, which may be incorporated into a substantially flat surface130 for example, is couplable with a pinless power plug 120. The pinlesspower jack 110 includes an annular primary coil 112 shielded behind aninsulating layer, which may be hardwired to a power source 102 via adriving unit 104. Driving electronics may include a switching unitproviding a high frequency oscillating voltage supply, for example.

The pinless power plug 120 includes an annular secondary coil 122 thatis configured to inductively couple with the primary coil 112 of thepinless power jack 110 to form a power transferring couple that isessentially a transformer. Optionally, a primary ferromagnetic core 114is provided in the pinless power jack 110 and a secondary ferromagneticcore 124 is provided in the pinless power plug 120 to improve energytransfer efficiency.

It will be appreciated that known pinned power couplings of the priorart cannot be readily incorporated into flat surfaces. The nature of anypinned coupling is that it requires a socket into which a pin may beinserted so as to ensure power coupling. In contradistinction, thepinless power coupling 100 of the second embodiment of the invention hasno pin or socket and may, therefore, be incorporated behind the outerface of a flat surface 130, such as a wall, floor, ceiling, desktop,workbench, kitchen work surface, shelf, door or the like, at a locationwhere it may be convenient to provide power.

It is specifically noted that because the primary coil 112 of the secondembodiment is annular in configuration, alignment of the primary coil112 to the secondary coil 122 is independent of the angular orientationof the pinless power plug 120. This allows the pinless power plug 120 tobe coupled to the pinless power jack 110 at any convenient angle to suitthe needs of the user and indeed to be rotated whilst in use.

For example, a visual display unit (VDU) may draw its power via apinless power plug 120 of the second embodiment aligned to a pinlesspower jack 110 of the second embodiment incorporated into a work desk.Because of the annular configuration of the coils 112, 122, the angle ofthe VDU may be adjusted without the pinless coupling 100 being broken.

Prior art inductive coupling systems are not easily rotatable. Forexample, in order to achieve partial rotation, the system described inU.S. Pat. No. 6,803,744, to Sabo, requires the coils to be connected byflexible wires or brushes to concentric commutators on the body of anon-conductive annular container. Even so, Sabo's system allows rotationof only about half the intercoil angle. In contradistinction, thepinless power plug 120 of the second embodiment of the present inventionmay be rotated through 360 degrees or more, about the central axis ofthe annular primary coil 110 whilst continually maintaining the powercoupling 100.

It is known that inductive energy transfer is improved considerably bythe introduction of a ferromagnetic core 114, 124. By optimization ofthe coupling 100, appropriate electrical loads, such as standard lamps,computers, kitchen appliances and the like may draw power in the rangeof 10 W-200 W for example.

Three exemplary applications of the pinless power jack 110 of FIG. 2a ,are illustrated in FIGS. 2b-d , according to various embodiments of thepresent invention. With reference to FIG. 2b , a computer 140 a is shownconnected by a power cord 121 a to a first pinless power plug 120 a. Thepinless power plug 120 a is inductively coupled to a pinless power jack110 embedded in a desk top 130. The pinless power plug 120 a may therebydraw power from the pinless power jack 110 to power the computer 140 a,to charge its onboard power cells or both. The parameters such ascharging voltage and current for power provision to computers dependsupon the model of the computer and therefore the pinless power plug 120a may be adapted to provide a range of voltages, typically between 5-20Vand may transfer power at up to 200 W. Alternatively or additionally, avariety of pinless power jacks and/or pinless power plugs may beprovided which transfer various power levels for various appliances.

With reference to FIG. 2c , a light bulb 140 b connected to a lightsocket 121 b integral to a second pinless power plug 120 b is shown. Thepinless power plug 120 b may be inductively coupled to a pinless powerjack 110 by being aligned therewith, and supplies power directly to thelight bulb 140 b. It is noted that the voltage and power to be providedby the power plug 120 b depends upon the rating of the specific lightbulb 140 b. The power jack 110 may be configured to provide anappropriate power level and voltage such as 1-12V for flash-light typebulbs or 110V for mains bulbs in North America or 220V for mains bulbsin Europe. Alternatively the secondary coil in the plug 120 b may bothtransmit and step down the voltage.

Referring now to FIG. 2d , a pinless power plug adaptor 120 c is shownhaving a conventional power socket 140 c thereupon, into which anelectrical load (not shown) may be plugged using a conventional powercable (not shown) with a conventional pinned plug thereupon. The pinlessplug adaptor 120 c is shown coupled to a power jack 110 embedded into aflat surface 130. It is noted that a pinless power plug adaptor 120 cmay be coupled with a pinless jack 110 thereby allowing electrical powerto be supplied to conventional electrical devices having pinned plugs.The pinless power plug adaptor 120 c is typically configured to providea mains voltage signal of 110V AC in North America or 220V AC in Europealthough other voltages, including DC voltages via an internal rectifiermay be provided where required.

The induction coils 112, 122 for use in the pinless power coupling 100may be made of coiled wires or they may be manufactured by a variety oftechniques such as screen printing, or etching, for example.

FIGS. 3a and 3b schematically represent an exemplary induction coil1200, according to a third embodiment of the invention in schematic andexploded views respectively. The induction coil 1200 is annular in formand is suitable for use as a primary coil 112 in a pinless power jack110 or for use as a secondary coil 122 in a pinless power plug 120. Thecoil is noted to provide a particularly good coupling for its overallsize. An induction coil 1200 is formed by stacking a plurality ofconducting rings 1202 a-e upon a base board 1214. The induction coil1200 is in contact with two point contacts 1212 a, 1212 b upon the baseboard 1214. Each conducting ring 1202 has a leading protruding contact1208 and a trailing protruding contact 1206 which protrude radially fromthe center of a split ring 1204 and are located on either side ofinsulating gap 1210.

The conducting rings 1202 a-e are stacked in such a manner that eachring is insulated from the rings adjacent to it. The insulating gaps1210 in the conducting rings 1202 are configured such that the leadingprotruding contact 1208 a of a first ring 1202 a makes contact with thetrailing protruding contact 1206 b of a second ring 1202 b. In turn theleading protruding contact 1208 b of the second ring 1202 b makescontact with the trailing protruding contact 1206 c of a third ring 1402c and so forth until all the rings 1202 a-e stack together to form aninduction coil 1200. The leading protruding contact of the final ring1208 e and the trailing protruding contact of the first ring 1206 a areextended to form electrical contact with contact points 1212 a, 1212 bupon the base board 1214. It will be appreciated that this configurationproduces an annular induction coil 1200 with a free central axis 1203which may accommodate inter alia a ferrite core, a magnetic alignmentmechanism (see below) and/or an optical signal transfer system (seebelow).

The individual rings 1202 a-e may be manufactured by a variety oftechniques such as by circuit sandwiching, circuit printing, fabricationprinting, circuit etching, stamping and the like. Although the inductioncoil 1200 of the third embodiment shown in FIGS. 3a and 3b consists of amere five rings 1202 a-e, it will be appreciated that the number ofrings that may be stacked to form induction coils in this manner mayvary considerably, as may their dimensions. Thus induction coils withthe desired properties may be formed.

Alignment Mechanisms

The efficiency of the power coupling 100, depends upon the alignmentbetween the secondary coil 122 of the pinless power plug 120 and theprimary coil 112 of the pinless power jack 110. Where the substantiallyflat surface 130 is fabricated from transparent material such as glassor an amorphous plastic, such as PMMA for example, the user is able tosee the pinless power plug 110 directly and may thus align the pinlessplug 120 to the pinless jack 110 by direct visual observation. However,where the substantially flat surface 130 is opaque alternative alignmentmechanisms 200 may be necessary. Such alignment mechanisms 200 mayinclude tactile, visual and/or audible indications, for example.

Tactile Alignment Mechanisms

With reference now to FIGS. 4a-c , three exemplary tactile alignmentmechanisms 210, 220, 230 are shown according to various embodiments ofthe invention. Referring particularly to FIG. 4a , a first tactilealignment mechanism 210 is shown wherein the pinless power jack 110includes a central magnetic snag 212 surrounded by an annular primarycoil 112 and the corresponding pinless power plug 120 includes a centralmagnetic anchor 214 surrounded by an annular secondary coil 122.

The primary coil 112 of this embodiment consists of a primary conductingwire 113, preferably a litz wire which is wound around a primaryferromagnetic core 114 and the secondary coil 122 consists of asecondary conducting wire 123, again preferably a litz wire which iswound around a secondary ferromagnetic core 124. When aligned, theprimary ferromagnetic core 114 and the secondary ferromagnetic core 124form a magnetic couple that increases the magnetic flux linkage betweenthe primary coil 112 and the secondary coil 122, allowing electricalenergy to be transmitted more efficiently therebetween.

The central magnetic snag 212 is configured to engage with the magneticanchor 214 carried by the pinless power plug 120, when the secondarycoil 122 is optimally aligned to the primary coil 112 of the pinlesspower jack 110. It will be appreciated that the attraction between themagnetic anchor 214 and the magnetic snag 212 may be felt by anoperator, thereby providing a tactile indication of alignment. Inaddition, the anchor-snag arrangement, once engaged, also serves to lockthe pinless power plug 120 into alignment with the pinless power jack110. The combination of a central circular magnetic snag 212 and aconcentric annular primary coil 112, allows the plug 120, having acentral magnetic anchor 214, to rotate around a central axis withoutlosing alignment and thus to be aligned at any orientation.

A second tactile alignment mechanism 220 is shown in FIG. 4b whereinpinless power jack 110 includes four magnetic corner snags 222 a-d whichare arranged at four points around primary coil 112, being a primaryconducting wire 113 wound around a primary ferromagnetic core 114. Thefour magnetic corner snags 222 a-d are configured to magnetically couplewith four magnetic corner anchors 224 a-d carried by a pinless powerplug 120, when the primary coil 112 and secondary coil 122 are aligned.

In embodiments where rotation of the secondary coil 122 may impedeenergy transfer or is otherwise undesirable, multiple magnetic snags 222may be used to limit the rotation of the plug 120 about its central axisto four specific alignment angles. At each of the compass points, thesecondary ferromagnetic core 124 is orientated and aligned to theprimary ferromagnetic core 114. The primary ferromagnetic core 114 andthe secondary ferromagnetic core 124 thus provided, form a magneticcouple that increases the magnetic flux linkage between the primary coil112 and the secondary coil 122, allowing electrical energy to betransmitted more efficiently therebetween. It will be appreciated thatthe number and configuration of multiple magnetic snags 222 and magneticanchors 224 may be selected to provide various multiple discretealignment angles.

With reference to FIG. 4c , a third tactile alignment mechanism 230 isshown, wherein the pinless power jack 110 includes an annular magneticsnag 232 concentric with a primary coil 112. The annular magnetic snag232 is configured to engage with an annular magnetic anchor 234concentric with a secondary coil 122 in a pinless plug 120. The annularconfiguration provides a free central axis which may be used toaccommodate an optical transmitter 310 and an optical receiver 320 of anoptical signal system for the regulation of power transfer. The thirdtactile alignment mechanism 230 allows the plug 120 to rotate around itscentral axis without compromising the alignment between the primary coil112 and the secondary coil 122, or between the optical transmitter 310and the optical receiver 320 of the optical signal system. The powerplug 120 may thus to be orientated at any angle to suit requirements.

For magnetic coupling, it will be appreciated that a permanent orelectro magnet in the jack may exert an attractive force on a secondpermanent or electromagnet in the plug. Alternatively, the plug may befitted with a piece of ferrous material that is attracted to a magnetbut is not itself, magnetic. Furthermore, the jack may include a pieceof iron that is attracted to a magnet, and the plug may be provided witha permanent or with an electromagnet. By way of illustration of this,with reference to FIGS. 5a-h , eight alternative magnetic alignmentmechanisms for use in coupling a pinless power plug 120 with a pinlesspower jack 110 are shown. A permanent magnetic snag 241 may couple withany of a permanent magnetic anchor 244, an electromagnetic anchor 245 ora ferromagnetic element 246. An electromagnetic snag 242 may couple withany of a permanent magnetic anchor 244, an electromagnetic anchor 245 ora ferromagnetic element 246. A ferromagnetic snag 243 may couple with apermanent magnetic anchor 244, or an electromagnetic anchor 245.

It is noted that a primary ferromagnetic core 114 of a pinless powerjack 110 may itself serve as a ferromagnetic snag 243. Alternatively,the primary coil 112 may serve as an electromagnetic snag 242. It isfurther noted that a secondary ferromagnetic core 124 of a pinless powerplug 120 may serve as a ferromagnetic anchor 246. Alternatively, thesecondary coil 122 may serve as an electromagnetic anchor 245.

A preferred magnetic alignment configuration is shown in FIG. 5aillustrating a permanent magnetic snag 241 configured to couple with apermanent magnetic anchor 244. The orientations of the magnetic snag 241and the magnetic anchor 244 are such that facing ends have oppositepolarity so that they are mutually attractive. It is noted that incertain embodiments two distinct types of pinless power jacks 120 areprovided for coupling with two distinct types of pinless power plugs,for example, a high power coupling and a low power coupling. In suchembodiments it is important to avoid a low power plug being aligned witha high power jack, for example. The magnetic anchors may preventincorrect coupling by using opposite polarities for each type ofcoupling. Thus, the low power plug may have North seeking polar magneticanchor, say, to engage with a South seeking polar magnetic snag on thelow power jack and the high power plug may have a South seeking polarmagnetic anchor to engage with a North seeking polar magnetic snag onthe high power jack. If the low power plug of this embodiment is placedproximate to the high power jack the North seeking polar anchor repelsthe North seeking polar snag and the couple can not be aligned.

It will be appreciated that, apart from magnetic mechanisms, otheranchor-and-snag type tactile alignment means may alternatively be usedsuch as suckers, hook-and-loop arrangements, ridge-and-groovearrangements and the like. Likewise these may be designed to selectivelycouple with only a selection of different power jacks in a commonsurface.

Visual Alignment Mechanisms

With reference to FIGS. 6a-e exemplary visual alignment mechanisms for apinless power plug 120 are shown. FIGS. 6a-c show a pinless power plug120 having a first visual indicator 250 consisting of two indicatorLEDs: a rough alignment indicating orange LED 252 and fine alignmentindicating green LED 254. A pinless power jack 110 is concealed beneathan opaque surface 130. FIG. 6a shows the pinless power plug 120 at alarge distance from the pinless power jack 110 with neither of the twoindicator LEDS being activated. FIG. 6b shows the pinless power plug 120partially aligned with the pinless power jack 110 and the orangeindicator LED 252 being lit up. This alerts a user that the plug 120 isin proximity with a pinless power jack 110, but is not properly alignedtherewith. Referring to FIG. 6c , when the pinless power plug 120 isoptimally aligned with the pinless power jack 110, the green indicatorLED 254 is activated to signal to a user that the plug 120 and(concealed) jack 110 are properly aligned and optimal power transfer ispossible.

FIG. 6d shows a second visual indicator consisting of a plurality ofLEDs in a strip 260; it being appreciated that a larger number of LEDsprovides for a greater degree of graduation in indication of proximity,and helps the user home in on the concealed jack. With reference to FIG.6e , showing a third visual indicator, instead of or in addition toLEDs, an LCD display 265 may provide an alternative visual indicator,which can, in addition to providing indication of the degree ofalignment, also provide indication of the current drawn by the loadcoupled to the plug, for example.

By their nature, LEDs are either illuminated or not illuminated, howeverProximity data may be encoded by flashing, frequency or the like. Theintensity of power supplied to other types of indicator lamps may beused to indicate the degree of coupling, or a flashing indicator lampmay be provided, such that the frequency of flashing is indicative ofdegree of alignment. Indeed, where the load is an incandescent lightsource or the like, it may be used directly for alignment purposes,since poor alignment results in a noticeable dimming affect.

Additionally or alternatively to plug-mounted visual indicators forjack-plug alignment surface-mounted visual indicators may be provided.Thus, with reference to FIGS. 7a-d , various exemplary visual alignmentmechanisms are shown located upon a flat surface 130 in which a pinlesspower jack 110 has been embedded. In FIG. 7a , showing a fourth visualindicator, a mark 270 has been made on the flat surface 130 directlyabove the concealed pinless power jack 110. This enables the user tophysically align the plug with the mark 270 and thus with the concealedjack FIG. 7b shows a fifth visual indicator 272 consisting of twoindicator LEDs embedded in the surface 130. This works as per theembodiment of FIGS. 6b and 6c , mutatis mutandis, to provide a graduatedindication of alignment. Similarly, FIG. 7c shows a sixth visualindicator 274 consisting of a plurality of LEDs in a strip embedded inthe surface 130 for a more graduated degree of alignment indication andFIG. 7d shows a seventh visual indicator 276 consisting of an LCDdisplay embedded in the surface 130.

Audible Alignment Mechanisms

Non-visual alignment means may alternatively or additionally be providedfor example, an audible signal may assist the visually impaired attainalignment. As shown in FIG. 8a , a pinless power plug 120 may include abuzzer 280. The buzzer 280 may be configured to provide graduatedindication of proximity to alignment for example by variation in tone,pitch, volume, timbre, beep frequency or the like. Alternatively anaudible alignment means may be surface-mounted as shown in FIG. 8b ,showing a buzzer 285 embedded in the surface 130, configured to buzz ina manner indicating whether there is, and extent of alignment.

Power Regulation

Efficient power transfer requires regulation. In order to regulate thecharacteristics of the power provided to the secondary coil 122, such asvoltage, current, temperature and the like, feedback from the device tothe power jack 110 is desirable. According to further embodiments of thepresent invention, a power regulator 300 provides a communicationschannel between the power plug 120 wired to the load and the power jack110.

A first exemplary power regulator 300 is illustrated in FIG. 9. Anoptical transmitter 310, such as a light emitting diode (LED), may beincorporated within the pinless power plug 120 and operably configuredto transmit electromagnetic radiation of a type and intensity capable ofpenetrating both the casing 127 of the pinless power plug 120, and ashielding layer 132 of the substantially flat surface 130. An opticalreceiver 320, such as a photodiode, a phototransistor, a light dependentresistors or the like, is incorporated within the pinless power jack 110for receiving the electromagnetic radiation transmitted through thesurface layer 132. In preferred embodiments the optical transmitter 310and the optical receiver 320 are configured along the axis of theannular primary coil 112. This permits alignment to be maintainedthrough 360 degree rotation of the pinless power plug 120.

It is noted that many materials are partially translucent to infra-redlight. It has been found that relatively low intensity infra red signalsfrom LEDs and the like, penetrate several hundred microns of commonmaterials such as plastic, cardboard, Formica or paper sheet, to asufficient degree that an optical receiver 320, such as a photodiode, aphototransistor, a light dependent resistor or the like, behind a sheetof from 0.1 mm to 2 mm of such materials, can receive and process thesignal. For example a signal from an Avago HSDL-4420 LED transmitting at850 nm over 24 degrees, may be detected by an Everlight PD15-22C-TR8 NPNphotodiode, from behind a 0.8 mm Formica sheet. For signaling purposes,a high degree of attenuation may be tolerked, and penetration of only asmall fraction, say 0.1% of the transmitted signal intensity may besufficient. Thus an infra-red signal may be used to provide acommunication channel between primary and secondary units galvanicallyisolated from each other by a few hundred microns of common sheetmaterials such as wood, plastic, Formica, wood veneer, glass etc.

Where the intermediate surface layer is opaque to infra-red,particularly where the intermediate surface layer is relatively thick,an optical path may be provided to guide the signal to the opticalreceiver 320. Typically, the optical path is a waveguide such as anoptical fiber, alternatively, the optical receiver 320 may be placedbehind an opening in the face of the surface and covered with atranslucent window.

In inductive couples, the communication channel may be used to transferdata between the primary and the secondary coils. The data transferredmay be used to regulate the power transfer, for example. Typically thesignal carries encoded data pertaining to one or more items of the listbelow:

the presence of the electric load;

the required operating voltage for the electric load;

the required operating current for the electric load;

the required operating temperature for the electric load;

the measured operating voltage for the electric load;

the measured operating current for the electric load;

the measured operating temperature for the electric load, or

a user identification code.

Such a signal may be useful in various inductive energy couples usablewith the present invention such as transformers, DC-to-DC converters,AC-to-DC converters, AC-to-AC converters, flyback transformers, flybackconverters, full-bridge converters, half-bridge converters and forwardconverters.

Referring now to FIG. 10, a block diagram is presented illustrating themain features of an exemplary signal transfer system for initiating andregulating inductive power transfer according a second embodiment of thepower regulator 300. An inductive power outlet, such as a pinless powerjack 110, is configured to couple with a secondary unit, such as apinless power plug 120, separated therefrom by a surface layer 130.Power is transferred to an electric load 140 wired to the pinless powerplug 120.

The pinless power jack 110 includes a primary inductive coil 112, ahalf-bridge driver 103, a multiplexer 341, a primary microcontroller343, a tone detector 345 and an optical receiver 347. The secondaryunit, such as pinless power plug 120, consists of a secondary coil 122,a receiver 342, a secondary microcontroller 344, an optical transmitter346 and a load connecting switch 348.

The primary inductive coil 112 of the inductive power outlet is drivenby the half-bridge driver 103 which receives a driving signal S_(D) fromthe multiplexer 341. The multiplexer 341 selects between aninitialization signal S_(I) or a modulation signal S_(M). Theinitialization signal S_(I) provides a detection means for activatingthe inductive power outlet 110 when a secondary unit 120 is present.Once active, the modulation signal S_(M) provides a means for regulatingpower transfer from the power outlet 110 to the secondary unit 120.

Secondary unit detection is provided by the primary microcontroller 343intermittently sending an initialization signal S_(I) to the multiplexer341 when the power outlet 110 is inactive. The multiplexer 341 relaysthe initialization signal S_(I) to the half-bridge driver 103, whichresults in a low powered detection pulse being transmitted by theprimary coil 112. If a secondary unit 120 is aligned with the inductivepower outlet 110, the low powered detection pulse is inductivelytransferred to the secondary coil 122 across the surface layer 130. Thereceiver 342 is configured to receive this detection pulse and relay adetection signal to the secondary microcontroller 344 which sends asignal to the load connector switch 348 to connect the load and triggersthe optical transmitter 346 to transmit an optical signal through thesurface layer 130 confirming that the secondary unit 120 is in place.The optical signal is received by the optical receiver 347 in the poweroutlet 110, and is then relayed to the tone detector 345 which sends aconfirmation signal to the primary microcontroller 343. The primarymicrocontroller 343 then activates the power outlet 110 by triggeringthe multiplexer 341 to select the modulation signal S_(M) to regulatethe power transfer.

The modulation signal S_(M) comes directly from the optical receiver 347and is used to regulate the duty cycle of the half-bridge driver 103.Power transferred to the secondary unit 120 is monitored by thesecondary microcontroller 344. The secondary microcontroller 344generates a modulation signal S_(M) and sends it to the opticaltransmitter 346, which transmits a digital optical signal. Themodulation signal S_(M) is thus received by the optical detector 347 ofthe primary unit 110, relayed to the multiplexer 341 and used toregulate the half-bridge driver 103.

Prior art inductive power transfer systems control and regulate powerfrom the primary unit 110. In contradistinction, it is a feature of thissecond embodiment of the power regulator that the power transfer isinitiated and regulated by a digital signal sent from the secondary unit120. One advantage of this embodiment of the invention is that theregulation signal is determined by the secondary microcontroller 344within the pinless power plug 120, which is hard wired to the load.Therefore, conductive communication channels to the secondarymicrocontroller 344 may be used to transmit analogue signals to thesecondary microcontroller 344 for monitoring the power transfer and adigital signal may be used for communicating between the pinless powerplug 120 and the pinless power jack 110.

Multicoil Systems

Alignment of a pinless power plug to a pinless power jack may befacilitated by using a plurality of induction coil and therebyincreasing the number of alignment locations.

A plurality of pinless power jacks 110, identified, for example, as 110a-c, are shown in FIG. 11a arranged into a power array 1100 covering anextended surface 1300 according to still a further embodiment of theinvention. The power array 1100 allows for a pinless power plug 120 tobe aligned with a power jack 110 in a plurality of locations over thesurface 1300. It is noted that although a rectangular arrangement isrepresented in FIG. 11a , other configurations such as a hexagonal closepacked arrangement, for example, may be preferred. Optionally, as shownin FIG. 11b , multiple layers 111 a, 111 b of overlapping power jacks110 may be provided. Since a power plug 121 may be placed in alignmentwith any of the power jacks 110, a power supplying surface 1301 may beprovided which can provide power to a plug 121 placed at almost anylocation thereupon, or even to a plug in motion over the power supplyingsurface 1301.

With reference to FIG. 11c , two pinless power plugs 120A, 120B areshown lying upon a single power array 1100 including a plurality ofembedded jacks. The plugs 120A, 120B are free to move parallel to thesurface 1300 as indicated by the arrows. As a plug 120, moving along thepower array 1100, approaches a jack 110, an anchor 214 associated withthe plug 120 couples with a snag 212 associated with a jack 110 sobringing the primary coil 112 into alignment with a secondary coil 122.

When a power plug 120A lies between two jacks 110 k, 1101, its anchor214 a is not engaged by any snag 212. Consequently, the secondary coil122A of the power plug 120A is not aligned with any primary coil 112. Insuch a situation an orange LED indicator 252A for example, may be usedto indicate to the user that the plug 120A is close to but not optimallyaligned with a primary coil 112. Where a power plug 120B lies directlyin line with power jack 110 b such that its anchor 214B is engaged by asnag 212 b embedded in the power jack 110 b, the secondary coil 122B isoptimally aligned to the primary coil 112 b of the jack 110 b and thismay be indicated for example by a green LED indicator 254B.

Reference is now made to FIG. 11d showing a power plug 1200 providedwith multiple secondary coils 1202 a, 1202 b according to anotherembodiment of the invention. Efficient inductive power transfer mayoccur when either one of the power plug's secondary coils 1202 isaligned to any primary coil 112. It is noted that known multicoiledpower plugs such as the double coiled plug described in U.S. Pat. No.6,803,744, to Sabo, need to be specifically and non-rotatably alignedsuch that the two secondary coils are both coupled to primary coilssimultaneously. In contradistinction to the prior art, in themulticoiled power plug 1200 of the present embodiment of the invention,only one secondary coil 1202 aligns with one primary coil 110 at a time.Alignment may thereby be achieved at any angle and the multicoiled powerplug 1200 may be rotated through 360 degrees or more about the axis X ofthe primary coil 110.

Furthermore, in the multicoiled power plug 1200, the distance betweenthe secondary coils 1202 may advantageously be selected to differ fromthe inter-coil spacing of the power platform array 1100. The multicoilpower plug 1200 may then be moved laterally over the power surface 1100and the driving unit of the power array 1100 may activate the primarycoils located closest to the multicoil power plug 1200. As the multicoilpower plug 1200 is moved laterally, the secondary coils 1202 a, 1202 bboth receive power from the primary coils in their vicinity. The powertransferred to both the secondary coils 1202 a, 1202 b undergoes diodesummation to produce a total voltage output. Because the two secondarycoils 1202 a, 1202 b are never both aligned simultaneously, the totaloutput voltage is smoothed and power fluctuations normally associatedwith power transfer to moving power plugs may be prevented. Thisincreases overall efficiency and reduces the need for large variationsin the power provided to the power array 1100.

Inductive power transfer models have been simulated to measure theefficiency of power transfer to multiple secondary coils from a powersurface with inter coil separation of 8.8 cm. With voltage applied onlyto the primary coil closest to a pair of secondary coils separated by4.4 cm (half the surface intercoil separation), the efficiency of totalenergy transferred to the pair of secondary coils does not fall below80% as the pair of secondary coils undergoes lateral translation alongthe surface. This efficiency is further improved by increasing thenumber of secondary coils, for example in simulations of a triplet ofsecondary coils spaced at 2.9 cm from each other, efficiencies of 90%were achieved.

Returning to FIG. 11b , each layer 111 a, 111 b of primary coil array1101 is offset from the others, for example, by half the surfaceintercoil separation. At least one single coiled pinless power plug 121with multiple secondary coils 122 may be placed upon the multilayeredpower surface 1301 and the driving unit of the power surface configuredto activate only the primary coils within the multilayered power surfacelocated closest to alignment with the secondary coils of the power plug121 regardless of the distance of the layer 111 a, 111 b from the powerplug 121. In most preferred embodiments the overlapping jacks 110 areoffset by a distance which is different from an intercoil spacing of thesecondary coils 122 in the at least one power plug 121. In this way, thevoltage, efficiency, and power transferred to the secondary coils 122are greatly stabilized.

Power arrays 1100 may be incorporated within any flat surface 1300 whereit is convenient to provide power. Such surfaces include walls, floorareas, ceilings, desktops, workbenches, kitchen work surfaces andcounter tops, shelves, doors and door panels and the like.

For example, FIG. 12a shows an exemplary horizontal power array 1100 anda pinless power plug 120 a electrically coupled to a computer 140 a bymeans of a connecting cable 121 a. The pinless power plug 120 a isplaced upon the power array 1100 and is inductively coupled to a pinlesspower jack 110 therewithin. Power supplied to the computer 140 a maypower the computer 140 a directly and/or recharge a rechargeable powercell thereof. The arrangement of FIG. 12a with pinless power plugs 120 aconnected by cables 121 a, typically reduces the length and number ofwires and cables 121 a necessary when connecting a computer 140 a to apower source, and thus may be beneficial in conference rooms and thelike, where such wires are obstructing, unsightly and generallyinconvenient. It is noted that the pinless power plug 120 a mayalternatively be integral to the computer 140 a, and the connectingcable 121 a thereby dispensed with altogether.

FIG. 12b shows an exemplary power array 1100 that is inverted andhorizontal for fixing to a ceiling, for example. Two pinless lightingplugs 120 b carrying light sockets 121 b for accommodating light bulbs140 b are shown. The lighting plugs 120 b are movable and may be coupledto any one of the plurality of pinless power jacks 110 of the powerarray 1100. In a preferred embodiment, strong magnetic anchors 214carried by the lighting plugs 120 a exert a force upon the magneticsnags 212 embedded in the power array 1100 of sufficient strength tosupport the weight of the lighting plugs 120 a. In this way, pinlesslighting plugs 120 a may be easily moved and reattached at differentlocations around the power array 1100.

It will be noted that the power array 1100 shown in FIG. 12b isinverted, allowing lighting plugs 120 b to be suspended therebeneath.For many lighting applications, such as for the lighting of a room, suchan arrangement is preferred as overhead lighting is less likely to beobscured by objects than lower level lighting. However a lighting powersurface may be hung vertically or embedded into a wall, or indeed placedunderfoot or in any other orientation.

It is noted that domestic incandescent light bulbs generally requirepower in the range of 10-150 watts, it is thus desirable for a lightingplug 120 b to supply electricity at this power. The inductivetransmission of energy in this power range is enabled by the efficientalignment of highly efficient coils such as that shown in theconfiguration of FIGS. 3a and 3b described herein. Low power lightingsolutions, such as fluorescent bulbs, LEDs and the like, typically uselower power plugs.

With reference to FIG. 12c , an exemplary vertical power array 1100 c isshown which may for example be incorporated into the wall of a room,mounted onto the side of a cabinet or other vertical surface. The powerarray 1100 c is used for providing moveable power outlets 120 d intowhich a pinned plug connected to a power cable (not shown) may beplugged, for coupling an electric load to an inductive power jack 110and thereby providing power to the electric load.

Two movable power outlets 120 d are also shown. Each outlet 120 dincludes a magnetic anchor 214 which may be of sufficient strength tosupport the weight of the movable power outlet 120 d when coupled to amagnetic snag 212 embedded in the vertical power array 1100 c. Suchpower outlets 120 d may thus be freely moved around the vertical powerarray 1100 c and located at any position which is aligned to a pinlesspower jack 110. Furthermore, although a vertical power array 1100 c isshown in FIG. 12c , it will be apparent that movable power outlets 120 dmay be coupled to a power array 1100 in any orientation.

FIG. 13 is a flowchart showing a method for transferring an opticalsignal between a primary unit and a secondary unit via an intermediatelayer. The method comprises the following steps: an optical transmitteris incorporated within the secondary unit—step (a); an optical receiveris incorporated within the primary unit—step (b); the opticaltransmitter transmits electromagnetic radiation of a type and intensitycapable of penetrating the surface layer—step (c); and the opticalreceiver receives the electromagnetic radiation—step (d).

It will be appreciated that such a method may be applicable totransmitting a regulation signal for regulating power transfer across aninductive coupling by monitoring at least one operating parameter ofsaid electric load and encoding the monitored parameter data into saidoptical signal. Similarly, data relating to the presence of an electricload, its power requirements, operating voltage, operating current,operating temperature or the like may be communicated.

The scope of the present invention is defined by the appended claims andincludes both combinations and sub combinations of the various featuresdescribed hereinabove as well as variations and modifications thereof,which would occur to persons skilled in the art upon reading theforegoing description.

In the claims, the word “comprise”, and variations thereof such as“comprises”, “comprising” and the like indicate that the componentslisted are included, but not generally to the exclusion of othercomponents.

We claim:
 1. An inductive power transfer system comprising: a power-outlet positioned on a side of a surface layer, the power-outlet comprising: at least one primary coil; a driver for driving the at least one primary coil; an electromagnetic radiation receiver; and a secondary unit positioned on an opposite side of the surface layer, wherein the secondary unit is used to supply power to a load and comprising: at least one secondary coil used to receive power transmitted by the at least one primary coil; and an electromagnetic radiation transmitter configured to transmit to the electromagnetic radiation receiver a modulation signal that is based at least in part on monitoring said power to the load; and wherein the modulation signal provides at least one indication of alignment of the at least one secondary coil with respect to the at least one primary coil and to regulate a duty-cycle of the driver.
 2. The inductive power transfer system of claim 1, wherein the at least one primary coil is arranged in an array, wherein the power-outlet further comprises at least one additional primary coil arranged in an additional-array, and wherein the at least one primary coil is arranged in a way that overlaps the at least one additional primary coil.
 3. The inductive power transfer system of claim 1, wherein the at least one primary coil is activated selectively based on the at least one indication of alignment.
 4. The inductive power transfer system of claim 1, wherein the secondary unit further comprises an indicator for providing the at least one indication of alignment, wherein the indicator is selected from a group consisting of: visual indicator; audible indicator; tactile indicator; and any combination thereof.
 5. The inductive power transfer system of claim 1, wherein the driver selectively drives the at least one primary coil.
 6. The inductive power transfer system of claim 1, wherein the power-outlet further comprises a multiplexer configured to select between an initialization signal and the modulation signal for driving the at least one primary coil.
 7. The inductive power transfer system of claim 6, wherein the initialization signal drives the at least one primary coil for generating a low power detection signal while the power-outlet is not coupled with the secondary unit.
 8. The inductive power transfer system of claim 6, wherein the modulation signal drives the at least one primary coil while the power-outlet is coupled with the secondary unit.
 9. The inductive power transfer system of claim 1, wherein the modulation signal is related to parameters of the load that are selected from a group consisting of operating voltage; operating current; operating temperature; and any combination thereof.
 10. The inductive power transfer system of claim 1, wherein the electromagnetic radiation transmitter is a light emitting diode operating in visible spectrum.
 11. A power-outlet to be positioned on a side of a surface layer for inductively powering a secondary unit to be positioned on an opposite side of the surface layer, wherein the secondary unit that supplies power to a load has at least one secondary coil and an electromagnetic radiation transmitter, the power-outlet comprising: at least one primary coil used for the powering the at least one secondary coil; a driver for driving the at least one primary coil; an electromagnetic radiation receiver used for receiving from the electromagnetic radiation transmitter a modulation signal that is based at least in part on monitoring of the power to the load; and wherein the modulation signal provides an indication of alignment of the at least one secondary coil with respect to the at least one primary coil and to regulate a duty-cycle of the driver.
 12. The power-outlet of claim 11, wherein the at least one primary coil is arranged in an array, wherein the power-outlet further comprises at least one additional primary coil arranged in an additional-array, and wherein the at least one primary coil is arranged in a way that overlaps the at least one additional primary coil.
 13. The power-outlet of claim 12, wherein the at least one primary coil is activated selectively based on the indication of alignment.
 14. The power-outlet of claim 11, wherein the driver selectively drives the at least one primary coil.
 15. The power-outlet of claim 11, wherein the power-outlet further comprises a multiplexer configured to select between an initialization signal and the modulation signal for driving the at least one primary coil.
 16. The power-outlet of claim 15, wherein the initialization signal drives the at least one primary coil for generating a low power detection signal while the power-outlet is not coupled with the secondary unit.
 17. The power-outlet of claim 15, wherein the modulation signal drives the at least one primary coil while the power-outlet is coupled with the secondary unit.
 18. The power-outlet of claim 11, wherein said modulation signal is related to parameters of the load that are selected from a group consisting of operating voltage; operating current; operating temperature; and any combination thereof.
 19. A secondary unit to be positioned on a side of a surface layer for suppling power to a load, wherein the secondary unit is inductively powered by a power-outlet to be positioned on an opposite side of the surface layer, wherein the power-outlet has at least one primary coil and an electromagnetic radiation receiver, the secondary unit comprising: at least one secondary coil used to receive power transferred by the at least one primary coil; an electromagnetic radiation transmitter used for transmitting a modulation signal to the electromagnetic radiation receiver, wherein the modulation signal is based at least in part on monitoring of power supplied to the load; and wherein the power-outlet utilizes the modulation signal for providing at least one indication of alignment of the at least one secondary coil with respect to the at least one primary coil and to regulate the power transferred by the at least one primary coil.
 20. The secondary unit of claim 19, further comprising at least one indicator for providing the at least one indication of alignment, wherein the indicator is selected from a group consisting of: visual indicator; audible indicator; tactile indicator; and any combination thereof.
 21. The secondary unit of claim 19, wherein the modulation signal drives the at least one primary coil while the power-outlet is coupled with the secondary unit.
 22. The secondary unit of claim 19, wherein said modulation signal is related to parameters of the load that are selected from a group consisting of operating voltage; operating current; operating temperature; and any combination thereof.
 23. The secondary unit of claim 19, wherein the electromagnetic radiation transmitter is a light emitting diode operating in the visible spectrum. 